One-piece molding die and molding method for a spherical plain bearing without assembly

Abstract

The present invention discloses an integrated forming mold and forming method for a joint bearing that does not require assembly, the forming mold comprising an inner ring mold and an outer ring mold, the inner ring mold being provided with a cavity and a positioning hole that match the inner ring of the joint bearing, the inner ring mold being formed by docking an inner ring mother mold and an inner ring mold, and being used in conjunction with a positioning core shaft; the outer ring mold being provided with a cavity that matches the outer ring of the joint bearing, a cavity that matches part of the inner ring of the joint bearing, and a positioning hole, the outer ring mold being formed by docking an outer ring mother mold and an outer ring mold, and being used in conjunction with a positioning core shaft; the present invention can first prepare the inner ring of the joint bearing through the inner ring mold, and then place the inner ring of the joint bearing in the outer ring mold to directly prepare an integrated component of the joint bearing, and the production of ceramic joint bearings can avoid the disadvantages of uneven force and small load-bearing capacity caused by the structure, and can also avoid damage to the inner and outer rings during the assembly process.

Description

Technical Field

[0001] The present invention relates to the technical field of bearing manufacturing, and in particular to an integral molding die and a molding method for a spherical bearing that does not require assembly. Background Art

[0002] Spherical plain bearings (Spherical plain bearings) feature a simple structure, high load capacity, high reliability, and easy maintenance. They are suitable for applications involving reciprocating motion, heavy loads, and slow sliding speeds. They are commonly used for transmission, rotation, connection, and support structures, and are widely used in aerospace, robotics, rail transportation, engineering machinery, marine equipment, and other fields. With the development of high-tech fields such as aerospace and shipbuilding, the demand for Spherical plain bearings with lightweight, heavy-duty, high-temperature, and corrosion-resistant properties is increasing. This has led to the emergence of ceramic Spherical plain bearings. However, due to the limitations of ceramic materials, the inner and outer rings of ceramic Spherical plain bearings cannot be assembled using the same method as conventional Spherical plain bearings.

[0003] Currently, there are several methods for producing ceramic spherical plain bearings: The first method involves manufacturing the inner and outer rings separately. Notches are machined into the outer ring to ensure symmetrical distribution, with a width equal to the width of the inner ring. The inner ring is then placed upright inside the outer ring, ensuring a spherical fit between the two. Due to the notches on the inner side of the outer ring, the outer ring is subjected to uneven force and has a low load-bearing capacity, which in turn affects the performance of the spherical plain bearing. The second method involves dividing the outer ring into a left and right half. During assembly, the two halves are fitted over the outer ring, followed by a protective sleeve. The sleeve and the outer ring form an interference fit. Because the outer ring consists of two halves, the outer ring is subjected to uneven force during use, reducing the service life of the spherical plain bearing. After extended use, the two halves can produce displacement errors, accelerating friction damage to the inner ring. This requires high assembly precision, but results in low production efficiency and high production costs. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides an one-piece molding mold and molding method for a joint bearing that does not require assembly. No assembly is required when preparing the joint bearing, which can avoid the disadvantages of uneven force and small load-bearing capacity caused by the structure, and can also avoid damage to the inner and outer rings during the assembly process.

[0005] The technical solutions of the present invention are as follows:

[0006] In a first aspect of the present invention, an integral molding mold for a spherical bearing that does not require assembly is provided, comprising an inner ring mold and an outer ring mold, wherein the inner ring mold is provided with a cavity and a positioning hole that match the inner ring of the spherical bearing, and the inner ring mold is formed by docking an inner ring mother mold and an inner ring ring mold, and is used in conjunction with a positioning core shaft; the outer ring mold is provided with a cavity that matches the outer ring of the spherical bearing, a cavity that matches part of the inner ring of the spherical bearing, and a positioning hole, and the outer ring mold is formed by docking an outer ring mother mold and an outer ring ring mold, and is used in conjunction with a positioning core shaft.

[0007] In some embodiments of the present invention, the inner ring mold also includes an inner ring press head, which is an annular structure. The outer diameter of the inner ring press head is the same as the diameter of the upper end hole of the inner ring mold, and the inner diameter of the inner ring press head is the same as the diameter of the positioning core shaft.

[0008] In some embodiments of the present invention, the outer ring mold also includes an outer ring press head, which is an annular structure. The outer diameter of the outer ring press head is the same as the diameter of the upper end hole of the outer ring mold, and the annular end face of the outer ring press head fits with the end face of the outer ring of the spherical bearing.

[0009] In some embodiments of the present invention, a positioning pin is provided on the inner ring mold, and a positioning hole is provided at a position corresponding to the positioning pin in the inner ring mother mold; a positioning pin is provided on the outer ring mold, and a positioning hole is provided at a position corresponding to the positioning pin in the outer ring mother mold, and the positioning pin cooperates with the positioning hole.

[0010] In some embodiments of the present invention, the positioning mandrel includes a base and a mandrel, and the base cooperates with the positioning hole in the inner ring mold or the positioning hole in the outer ring mold.

[0011] In some embodiments of the present invention, the diameter of the core shaft is the same as the inner diameter of the inner ring of the spherical plain bearing, and the height of the core shaft is greater than the height of the outer ring mold and the inner ring mold.

[0012] In a second aspect of the present invention, a method for integrally forming a spherical plain bearing without requiring assembly is provided, comprising the following steps:

[0013] Connect the inner ring mother mold and the inner ring mold, place the positioning mandrel in the positioning hole of the inner ring mold, pour the spherical plain bearing inner ring raw material from the mold port, and then compact the raw material with the inner ring press head;

[0014] After the inner ring of the spherical plain bearing is formed, it is placed in a normal pressure heating container for sintering;

[0015] Spray graphite powder on the outer surface of the sintered spherical plain bearing inner ring and attach a layer of flexible graphite paper, then place it on the positioning mandrel. Place the positioning mandrel in the positioning hole of the outer ring mold, pour the spherical plain bearing outer ring raw material from the mold port, and press it tightly with the outer ring press head;

[0016] After the outer ring of the spherical plain bearing is formed, the entire spherical plain bearing is placed in a normal pressure heating container for sintering;

[0017] The formed spherical plain bearing is taken out from the heating container, and then heated to 720℃-800℃ in an oxidation furnace to burn off the graphite paper layer to obtain the spherical plain bearing.

[0018] In some embodiments of the present invention, when the inner ring of the spherical plain bearing is sintered, a normal pressure heating container is sealed and filled with nitrogen. The pressure is controlled at 80 MPa-190 MPa, the sintering temperature is 1950° C.-2200° C., and the temperature is kept at this temperature for 1-2 hours.

[0019] In some embodiments of the present invention, when the spherical plain bearing is integrally sintered, a normal pressure heating container is sealed and filled with nitrogen. The pressure is controlled within the range of 2 MPa-8 MPa, the sintering temperature is 1200° C.-1350° C., and the temperature is kept for 1-3 hours.

[0020] In some embodiments of the present invention, the thickness of the graphite paper layer is 0.01 mm-0.1 mm.

[0021] One or more technical solutions of the present invention have the following beneficial effects:

[0022] (1) The forming mold provided by the present invention includes an inner ring mold and an outer ring mold. The inner ring of the spherical plain bearing can be first prepared by the inner ring mold, and then the inner ring of the spherical plain bearing is placed in the outer ring mold to directly prepare an integrated component of the spherical plain bearing. The production of ceramic spherical plain bearings can avoid the disadvantages of uneven force and small load-bearing capacity caused by the structure, and can also avoid damage to the inner and outer rings during the assembly process.

[0023] (2) The molding method provided by the present invention can prepare an integral spherical bearing by spraying graphite powder on the outer wall surface of the inner ring of the spherical bearing and attaching flexible graphite paper. After that, the integral spherical bearing is placed in a pure oxygen atmosphere furnace and heated to 720℃-800℃ to burn off the graphite layer. The integral all-ceramic spherical bearing can be obtained, eliminating the process of assembling the inner and outer rings of the spherical bearing.

[0024] (3) The molding die of the present invention has a simple structure and is easy to implement. The process of preparing the spherical bearing is also relatively simple and does not require assembly, thereby improving the precision and production efficiency of the spherical bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the inner circle mold structure of the present invention;

[0026] Figure 2 This is a schematic structural diagram of the inner ring mother mold of the present invention;

[0027] Figure 3 A schematic diagram of the pressed cross-sectional structure of the inner ring of the spherical plain bearing of the present invention;

[0028] Figure 4 A schematic structural diagram of the outer ring mold of the present invention;

[0029] Figure 5 A schematic structural diagram of the outer ring mother mold of the present invention;

[0030] Figure 6 A schematic diagram of the pressed cross-sectional structure of the spherical plain bearing outer ring of the present invention;

[0031] Figure 7 Schematic diagram of the inner ring of the spherical plain bearing prepared by the present invention;

[0032] Figure 8 Schematic diagram of the outer ring of the spherical plain bearing prepared by the present invention;

[0033] Figure 9 Overall schematic diagram of the spherical plain bearing prepared by the present invention.

[0034] In the figure: 1-ceramic spherical plain bearing inner ring; 2-ceramic spherical plain bearing outer ring; 3-inner ring pressure head; 4-inner ring mother mold; 41-inner ring mother mold positioning hole; 42-inner ring mother mold core shaft positioning surface; 43-inner ring mother mold core shaft positioning hole; 44-inner ring mother mold end face; 5-inner ring mold; 51-inner ring mold positioning pin; 52-inner ring mold core shaft positioning surface; 53-inner ring mold core shaft positioning hole; 54-inner ring mold end face; 6-bearing outer ring pressure head; 7-outer ring mold; 71-outer ring mold positioning pin; 72-outer ring mold positioning surface; 73-outer ring mold core shaft positioning hole; 74-outer ring mold end face; 8-outer ring mother mold; 81-outer ring mother mold positioning hole; 82-outer ring mother mold core shaft positioning surface; 83-outer ring mother mold core shaft positioning hole; 84-outer ring mother mold end face; 9-positioning core shaft. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Example 1

[0037] In a typical embodiment of the present invention, Figure 1-6 As shown, an integrated molding die for a spherical bearing that does not require assembly is proposed, comprising an inner ring mold and an outer ring mold. The inner ring mold is used to prepare the inner ring of the spherical bearing, and the outer ring mold is used to prepare the outer ring of the spherical bearing.

[0038] Among them, the structure of the inner ring mold is as follows Figure 1 and Figure 2As shown, the inner ring mold is formed by connecting the inner ring mother mold 4 and the inner ring mold 5. The inner ring mold is provided with a cavity and a positioning hole that match the inner ring of the spherical bearing. Specifically, the outer shape of the inner ring mother mold 4 is a rectangular parallelepiped, and a curved groove is opened on the side of the rectangular parallelepiped. The curved groove includes a curved surface that matches the inner ring of the spherical bearing and a curved surface that matches the positioning core shaft. The positioning core shaft is positioned by the core shaft positioning surface 42 of the inner ring mother mold. The structure of the inner ring mother mold 5 is similar to that of the inner ring mother mold 4. The difference is that the inner ring mother mold end face 44 of the inner ring mother mold 4 is provided with There are multiple inner ring mother mold positioning holes 41, and multiple inner ring mold positioning pins 51 are set on the inner ring mold end face 54 of the inner ring mold 5. The positions of the inner ring mother mold positioning holes 41 and the inner ring mold positioning pins 51 correspond to each other. When the inner ring mother mold 4 and the inner ring mold 5 are docked, the inner ring mold positioning pins 51 are inserted into the inner ring mother mold positioning holes 41, and the inner ring mother mold end face 44 and the inner ring mold end face 54 fit tightly with each other. A cavity matching the inner ring of the spherical bearing and a positioning hole cooperating with the positioning core shaft are formed between the inner ring mother mold 4 and the inner ring mold 5.

[0039] like Figure 3 As shown, the inner ring mold also includes an inner ring press head 3. When preparing the inner ring of the spherical bearing, the raw material in the mold is compacted by the inner ring press head. The inner ring press head 3 is an annular structure. The outer diameter of the inner ring press head is the same as the diameter of the upper end hole of the inner ring mold, and the inner diameter of the inner ring press head is the same as the diameter of the positioning core shaft. The positioning core shaft 9 includes a base and a core shaft. The base and the core shaft are both cylindrical. When in use, the base is placed in the positioning hole in the inner ring mold. The diameter of the core shaft is the same as the inner diameter of the inner ring of the spherical bearing, so as to realize the positioning of the spherical bearing during the preparation process. The cavity between the core shaft and the inner ring mold is the molding cavity of the inner ring of the spherical bearing.

[0040] The structure of the outer ring mold is as follows Figure 4 and Figure 5As shown, the outer ring mold is formed by connecting the outer ring mold 7 and the outer ring mother mold 8. The outer ring mold is provided with a cavity matching the outer ring of the spherical bearing, a cavity matching the inner ring of part of the spherical bearing, and a positioning hole. Specifically, the outer ring mold 7 is a cylinder, and a curved groove is opened on the side of the cylinder. The curved groove includes a curved surface matching the inner ring of the spherical bearing, a curved surface matching the inner ring of part of the spherical bearing, and a curved surface matching the positioning core shaft. The positioning core shaft is positioned by the positioning surface 72 of the outer ring mold. The structure of the outer ring mold 7 is similar to that of the outer ring mother mold 8. The difference is that the outer ring mother mold of the outer ring mother mold 8 A plurality of outer ring mother mold positioning holes 81 are provided on the end face 84 of the tool, and a plurality of outer ring mold positioning pins 71 are provided on the outer ring mold end face 74 of the outer ring mold 7. The positions of the outer ring mother mold positioning holes 81 and the outer ring mold positioning pins 71 correspond to each other. When the outer ring mold 7 and the outer ring mother mold 8 are docked, the outer ring mold positioning pins 71 are inserted into the outer ring mother mold positioning holes 81. The outer ring mold end face 74 and the outer ring mother mold end face 84 fit tightly with each other. A cavity matching the inner ring of the spherical bearing and a positioning hole matching part of the inner ring of the spherical bearing and cooperating with the positioning core shaft are formed between the outer ring mother mold 8 and the outer ring mold 7.

[0041] like Figure 6 As shown, the outer ring mold also includes an outer ring press head 6. When preparing the outer ring of the spherical bearing, the raw material in the mold is compacted by the outer ring press head. The outer ring press head 6 is an annular structure. The outer diameter of the outer ring press head is the same as the diameter of the upper end hole of the outer ring mold. The annular end face of the outer ring press head fits the end face of the outer ring of the spherical bearing. The positioning core shaft includes a base and a core shaft. The base and the core shaft are both cylindrical. When in use, the inner ring of the spherical bearing prepared by the inner ring mold is first installed on the positioning core shaft 9, and then the base of the positioning core shaft is placed in the positioning hole in the outer ring mold. The cavity between the inner ring of the spherical bearing and the outer ring mold is the molding cavity of the outer ring of the spherical bearing.

[0042] In order to facilitate the installation and disassembly of the positioning mandrel, the height of the mandrel of the positioning mandrel is set to be greater than the height of the outer ring mold and the inner ring mold.

[0043] Example 2

[0044] In a typical embodiment of the present invention, a method for integrally forming a spherical plain bearing without requiring assembly is provided, comprising the following steps:

[0045] Connect the inner ring mother mold and the inner ring mold, place the positioning mandrel in the positioning hole of the inner ring mold, pour the spherical plain bearing inner ring raw material from the mold port, and then compact the raw material with the inner ring press head;

[0046] After the inner ring of the spherical plain bearing is formed, it is placed in a normal pressure heating container for sintering;

[0047] Spray graphite powder on the outer surface of the sintered spherical plain bearing inner ring and attach a layer of flexible graphite paper, then place it on the positioning mandrel. Place the positioning mandrel in the positioning hole of the outer ring mold, pour the spherical plain bearing outer ring raw material from the mold port, and press it tightly with the outer ring press head;

[0048] After the outer ring of the spherical plain bearing is formed, the entire spherical plain bearing is placed in a normal pressure heating container for sintering;

[0049] The formed spherical plain bearing is taken out of the heating container and then heated to 720℃-800℃ in an oxidation furnace to burn off the graphite paper layer to obtain the spherical plain bearing. This step is achieved based on the different ignition points of graphite in oxygen and oxygen-free environments. The ignition point of graphite in an oxygen-free environment (nitrogen) is greater than 2200℃, and the ignition point in an oxygen environment is around 700℃. Therefore, it can ensure that the graphite paper layer of the inner ring of the spherical plain bearing will not be burned during sintering.

[0050] In this embodiment, when the inner ring of the spherical plain bearing is sintered, the normal pressure heating container is closed and filled with nitrogen. The pressure is controlled at 80 MPa-190 MPa, the sintering temperature is 1950° C.-2200° C., and the temperature is kept at this temperature for 1-2 hours.

[0051] In this embodiment, when the spherical plain bearing is integrally sintered, the normal pressure heating container is sealed and filled with nitrogen. The pressure is controlled within the range of 2 MPa-8 MPa. The sintering temperature is 1200° C.-1350° C. and the temperature is kept at this temperature for 1-3 hours.

[0052] In this embodiment, the thickness of the graphite paper layer is 0.01mm-0.1mm. The thickness of the graphite paper cannot be too large. If the thickness of the selected graphite paper is too large, the gap between the inner and outer rings after sintering will be large, which does not meet the clearance standard of the spherical plain bearing. By setting the thickness of the graphite paper between 0.01mm-0.1mm, it can be ensured that the spherical plain bearing meets the clearance standard.

[0053] Take the preparation of ceramic spherical bearings as an example:

[0054] Step 1: The raw materials of the ceramic spherical plain bearing inner ring are mixed according to the percentage of silicon carbide 73%-83%, phenolic resin 5%-12%, carbon black 1%-1.5%, graphite 1%-4%, polyvinyl alcohol 6%-9%, and boron carbide 0.5%-1% to form a silicon carbide ceramic raw material mixture. The particle size of the silicon carbide powder is 0.2-0.6 m.

[0055] Step 2: Place the inner ring mold locating pin into the inner ring mother mold locating hole, so that the inner ring mold end face is tightly attached to the inner ring mother mold end face; Place the locating mandrel into the inner ring mold locating hole, pour the mixed silicon carbide ceramic raw material from the mold port, and then use the inner ring press head to compact the raw material and pre-press for 1-2 minutes;

[0056] Step 3: Remove the inner ring of the spherical bearing from the mandrel, and then place it in a normal pressure heating container, seal the container, flush it with nitrogen, control the pressure within the range of 80Mpa-190Mpa, and sinter at a temperature of 1950℃-2200℃. Keep warm for 1-2 hours. Since the inner ring material is SiC ceramic, the sintering temperature of SiC is high and it is difficult to sinter. Increasing the pressure and sintering temperature is conducive to promoting sintering, and then naturally cool to room temperature.

[0057] Step 4: Take the inner ring of the spherical plain bearing out of the heating container, treat the outer surface of the sintered inner ring of the spherical plain bearing, spray graphite powder on it, and attach a layer of flexible graphite paper on the outer surface of the inner ring. The thickness of the graphite paper is between 0.01mm and 0.1mm.

[0058] Step 5: Place the sintered spherical plain bearing inner ring on the mandrel, place the mandrel in the positioning hole of the outer ring mold, and insert the positioning pin of the outer ring mold into the positioning hole of the outer ring mother mold so that the end face of the outer ring mold fits tightly with the end face of the outer ring mother mold.

[0059] Step 6: Mix 40%-95% alumina, 1%-40% zirconium oxide and 1%-2% combustion aid. The particle size of the raw materials is 0.2-0.7 m.

[0060] Step 7: Pour the mixed alumina ceramic raw materials into the outer ring mold port, compact the raw materials with the outer ring press head, and pre-press for 1-2 minutes to form a combination of the outer ring blank and the inner ring finished product.

[0061] Step 8: Place the obtained ceramic spherical bearing into a normal pressure heating container, seal the container, flush it with nitrogen, control the pressure within the range of 2Mpa-8Mpa, sinter the temperature at 1200℃-1350℃, and keep it warm for 1-3 hours. The outer ring is made of alumina, which has a lower sintering temperature and can be sintered at lower pressure and temperature, and then naturally cooled to room temperature.

[0062] Step 9: Take the formed ceramic spherical plain bearing out of the heating container, and then heat the bearing in an oxidation furnace to 720℃-800℃ to burn off the graphite layer, thus obtaining a full ceramic spherical plain bearing. The structure of the ceramic spherical plain bearing is as follows: Figure 7-9 shown.

[0063] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A one-piece molding method for a spherical bearing that does not require assembly, characterized in that: The mold of the molding method includes an inner ring mold and an outer ring mold. The inner ring mold is provided with a cavity and a positioning hole that match the inner ring of the spherical plain bearing. The inner ring mold is formed by connecting the inner ring mother mold and the inner ring mold, and is used in conjunction with a positioning mandrel. The outer ring mold is provided with a cavity that matches the outer ring of the spherical plain bearing, a cavity that matches part of the inner ring of the spherical plain bearing, and a positioning hole. The outer ring mold is formed by connecting the outer ring mother mold and the outer ring mold, and is used in conjunction with a positioning mandrel. Specifically: The inner ring mother mold and the inner ring mold are connected, the positioning mandrel is placed in the positioning hole of the inner ring mold, and the spherical plain bearing inner ring raw material is poured from the mold port; After the inner ring of the spherical plain bearing is formed, it is placed in a normal pressure heating container for sintering; Spray graphite powder on the outer surface of the sintered spherical plain bearing inner ring and attach a layer of flexible graphite paper, then place it on the positioning mandrel. Place the positioning mandrel in the positioning hole of the outer ring mold and pour the spherical plain bearing outer ring raw material from the mold port; After the outer ring of the spherical plain bearing is formed, the entire spherical plain bearing is placed in a normal pressure heating container for sintering. When the spherical plain bearing is sintered as a whole, the normal pressure heating container is closed and filled with nitrogen. The pressure is controlled within the range of 2Mpa-8Mpa, the sintering temperature is 1200℃-1350℃, and the temperature is kept at this temperature for 1-3 hours. The formed spherical plain bearing is taken out from the heating container, and then heated to 720℃-800℃ in an oxidation furnace to burn off the graphite paper layer to obtain the spherical plain bearing.

2. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 1, wherein: The inner ring mold also includes an inner ring press head, which is an annular structure. The outer diameter of the inner ring press head is the same as the diameter of the upper end hole of the inner ring mold, and the inner diameter of the inner ring press head is the same as the diameter of the positioning core shaft.

3. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 1, wherein: The outer ring mold also includes an outer ring press head, which is an annular structure. The outer diameter of the outer ring press head is the same as the diameter of the upper end hole of the outer ring mold, and the annular end face of the outer ring press head fits the end face of the outer ring of the spherical bearing.

4. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 1, wherein: An inner ring mold locating pin is provided on the inner ring mold, and an inner ring mother mold locating hole is provided at a position corresponding to the inner ring mold locating pin of the inner ring mother mold. An outer ring mold locating pin is provided on the outer ring mold, and an outer ring mother mold locating hole is provided at a position corresponding to the outer ring mold locating pin of the outer ring mother mold. The inner ring mold locating pin cooperates with the inner ring mother mold locating hole, and the outer ring mold locating pin cooperates with the outer ring mother mold locating hole.

5. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 1, wherein: The positioning core shaft includes a base and a core shaft, and the base cooperates with the positioning hole in the inner ring mold or the positioning hole in the outer ring mold.

6. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 5, wherein: The diameter of the core shaft is the same as the inner diameter of the inner ring of the spherical plain bearing, and the height of the core shaft is greater than the heights of the outer ring mold and the inner ring mold.

7. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 1, wherein: When sintering the inner ring of the spherical plain bearing, the normal pressure heating container is closed and filled with nitrogen. The pressure is controlled at 80Mpa-190Mpa, the sintering temperature is 1950℃-2200℃, and the temperature is kept at this temperature for 1-2 hours.

8. The one-piece molding method for a spherical plain bearing that does not require assembly according to claim 1, wherein: The thickness of the graphite paper layer is 0.01 mm to 0.1 mm.

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